Petroleum lubricants stabilized with bactericides



United States Patent ice My invention relates to a stabilized petroleumlubricant and more particularly to a process for the production ofstabilized petroleum lubricants containing as the active stabilizingagent nitrohexahydropyrimidines havingthe structural formula:

Il -N where R is lower alkyl and where R is selected from the groupconsisting of lower alkyl and lower hydroxyalkyl.

It is well known that organisms from the groups consisting ofCorynebacterium, Achromobacter, Pseudomohas, Nocardia and Mycobacteriummetabolize petroleum hydrocarbons and fatty acids and thereby produceundesirable oxidation products.

The petroleum industry has long been interested in the stabilization ofvarious petroleum products such as. cutting oils, hydraulic fluids,etc., against breakdown by bacteria which metabolize the hydrocarbonswith the concurrent formation of deleterious metabolites.

Many compounds havebeen used as stabilization agents in lubricants, butvery few have been found to be commercially successful due to the factthat the compounds are unstable,or are not active against a wide varietyof microorganisms.

Among the nitrohexahydropyrimidines having the above structural formulaare included 1,3-bis(1-hydroxymethylpropyl)--methyl 5nitrohexahydropyrimidine, 1,3-bis(2-hydroxyethyl) 5methyl-S-nitrohexahydropyrimidine, 1,3,5-trimethyl 5nitrohexahydropyrimidine,5-ethyl-l,3-dimethyl-5-nitrohexahydropyrimidine, S-ethyl-1,3-bis(2-ethylhexy )-5-nitrohexahydropyrimidine, 1,3-dicyclohexyl 5ethyl-5-nitrohexahydropyrimidine, S-ethyl-l,3-bis(hydroxy-t-butyl) 5nitrohexahydropyrimi dine, andS-ethyl-l,3-bis(2-hydroxypentyl)-5-nitrohexa hydropyrimidine. I havefound that in some instances I can obtain total inhibition of bacterialgrowth in petroleum lubricants at concentrations as low as 100 ppm.

I prefer to include at least 1,000 ppm. in most petroleum' formulations.However, I can'employ amounts up to about 2% by weight of the activenitroamines when the latter is soluble to this extent in the particularpetroleum hydrocarbon composition. 1 I'have found that my activeingredients are effective bacteriostatic agents in petroleum containinglubricants such as cutting oils, penetrating oils, grinding lubricants,iron tinning lubricants, core oils, hydraulic fluids, etc.

- The following examples set out lubricating composi- Patented May- 'I I1965 ting oil concentrate usediwas a-proprietary cutting oilcontions inwhich my active ingredients act as effective bacteriostatic agents. belimited to the compositions, portions, or lubricants set out below; butrather I intend for all equivalents and variations obvious to thoseskilled in the art to be included withinthe scope of this specificationand the attached It is not intended that my invention taining nobacterial inhibitors. soldi-byjTexaco Incorporated under the name ofSoluble Oil Texaco-C. To each of one-gallon containers wasadded lv literof water-cutting oil emulsion. Desired amounts -.ofmy'nitroa mines wereadded to the cutting-oil emulsion inthetfirstcontainer.

- No inhibitor was added. to the othercontainer which-was used as acontrol. At the beginningof' the experiment,

- each unit was inoculated with 5. mls. of a heterogeneous bacterialculture which had grown: for-several years in a water-cutting oilemulsion. Aeration and mixing were obtained by using an air lift to.continually. circulate the mixture. The tcst was continued for-aperiod-of six'weeks and .during the six-week period, 5 mls.'0fbacterial. culture were added at periodic weekly'intervals.

The following. table sets: out the results of'the above tests and thenumberof days ofbacteri al inhibition'when the described concentrationor the. desired nitrohexahy- 'dropyrimidines were incorporated into thecutting-oil emulsionj Table I Concentration NumberNitrohexahydropyrimidine in 25: of Days Water-Cutting Eflective OilEmulsion 1,3-bis(l-hydroxymethylpropyl)-5-methyl-fi-nitrohexahydropyrimidinc- 1, 000 '14 .'';-e th yl-l .3-hi(hydroxy-t-butyl)-5- dropyrimidiue 1,000 42fyethyl-l.3-1iis(hydroxy-t-hutyl)5- nitrohexahydropyrimidine Y 1,000 42Control '0 EXAMPLE II The following is a water emulsifiable cutting oilwhich EXAMPLE III The following is a'stabilized steam cylinder oil whichis adequately protected by 1,000 p.p'.m. of '5-ethyl'-1-,3-dimethyl-5-nitrohexahydropyrimidine.

I Percent S.A.E. lubricating oil '90 Oleic acid 10 EXAMPLE IV Thefollowing is a core oil which is adequatelyiprotected by 1,000 ppm. of1,3,S-trimethyl-Smitrohexa- EXAMPLE v The following is a cutting oilwhich isadequat'elyprotected by 1,000 p.-p.m. ofl,3'-bis(l-hydroxymethylpropyl)-5.-methyl-5-nitrohexahydropyrimidine.

Urea 0.4

: slow structural tiormula:

Now bailing described' my, invention; what 1 claim is: 1. A' -liquidpetroleum composition consisting essentially of a. liquid" petroleumlubricant'hydrocarbon and a suflicient amount ofl,3-bis(l-hydroxymethylpropyl) 5 methyl-S-nitrohexahydropyrimidine tostabilize said hydrocarbon against metabolizing bacteria. I v

2. Aliquid petroleumcomposition consisting essentially of a liquidpetroleum lubricant hydrocarbon and a suflicientamount ofl,3,5-trimethyl-S-nitroliexahydropyrimidine (to stabilize saidhydrocarbon against metabo- 35 A liquid petroleum composition consistingessen- I tislly of aliquid petroleum lubricant hydrocnrbon and ssufficient amount of S-ethyl-1,3-dirnethyl-5-nitrohexahydropyrimidine tometabolizing bacteria. a

stabilize; said hydrocarbon against '4. A liquid ,petroleumcompositionconsisting essentially of .a liquid petroleum lubricant-hydrocarbon anda sufficient. amount of S-ethyl-1,3-bis(hydroxy-t-butyl)-'S-nitrbhexahydropyrimidine to stabilize said hydrocarbon againstmetabolizing bacteria. p ,5. An aqueous petroleum emulsion consistingessentially'of an aqueous p'etroleumlubricant hydrocarbon emulsion and asuliicient amount of a nitrohexahydropyrimidine to stabilize saidhydrocarbon against metabolizinz bacteria, saidnitrohexahydropyrimidinehaving the d petroleum composition consistingessen- 6| tially -oie liquid petroleum lubricant hydrocarbon and asufiicient amount of a nitrohexnhydropyrimidine to stabilize saidhydrocarbon against metabolizing bacteria,

15 7. The composition of claim said nitrohexahydropyrimidine having thestructural formula: :11

f? 10 i NO wherein R-is lower alkylv andtvherein R is selected from the.group consisting of lower hydroxyalkyl and lower r 11. The compositionof claim Sywhereinthe composippm. to 2% by weight of tion contains fromabout 100 the nitrohexahydropyrir'nidine. v

I References Cited by the UNITED STATES PATENTS 12/45 Senkus 260-25111/57 Pennino 1671-43 11/59 -H0d36 252-515 macros: PATENTS 1 5/39Australia;

160,367 1155 Australia. 421,189 3/41 Italy.

DANIEL E. WYMAN, mm Eramineri wuus oRssnwALo, Examiner.

of claim 6 itvher'ein the composi of claim- 6 wherein thecornposi- 10.The composition ofelainr o-whenein'the composip.p.m. to 2% by weight of

5. AN AQUEOUS PETROLEUM EMULSION CONSISTING ESSENTIALLY OF AN AQUEOUSPETROLEUM LUBRICANT HYDROCARBON EMULSION AND A SUFFICIENT AMOUNT OF ANITROHEXAHYDROPYRIMIDINE TO STABILIZE SAID HYDROCARBON AGAINSTMETABOLIZING BACTERIA, SAID NITROHEXAHYDROPYRIMIDINE HAVING THESTRUCTURAL FORMULA: